1. Listening to sad music provokes more nostalgia than sadness.

People in the study reported that sad music brought up “a wide range of complex and partially positive emotions, such as nostalgia, peacefulness, tenderness, transcendence, and wonder,” write the study authors.

Surprisingly, nostalgia, rather than sadness, was the most frequently reported emotion.

2. Repetitive choruses are the key to a hit song.

Joseph Nunes at the University of South Carolina looked into what makes a song commercially successful in a paper published last year in the Journal of Consumer Psychology.

“Once you got on the hot 100, the more you repeated the chorus, the more word repetition, the less complex the song, the better it did,” Nunes told NPR earlier this year.

In fact, for each extra repetition of the chorus “a song’’s likelihood of making it to Number One, as opposed to staying at the bottom of the Billboard chart, increases by 14.5 percent,” Nunes and his co-authors wrote. There is a limit, though. Nunes and his colleagues saw a “ceiling affect”, above which more repetitions harmed, instead of helped, a song’s chances.

3. The “mere exposure effect” makes us like certain music just because we hear it a lot.

But, crucially, there’s a point at which it then really really starts to grate – and you get an inverted-U graph like the one above.

In an essay at Aeon, Elizabeth Hellmuth Margulis, director of the music cognition lab at the University of Arkansas, explains why repetition makes us like music: “People seem to misattribute their increased perceptual fluency – their improved ability to process the triangle or the picture or the melody – not to the prior experience, but to some quality of the object itself.”

Basically, hearing a song you’ve heard before makes you feel clever, because your brain has already figured it out.

4. The mere exposure effect might also explain why Christmas music is so divisive.

The “mere exposure effect” could have something to do with our love/hate relationship with Christmas music. We get exposed to a ton of it in a very short amount of time, which can take us all the way up the inverted-U graph and down again very quickly.

At the beginning of December, you might be feeling pretty good about hearing some festive tunes, but by the end you’re likely to be burnt out.

5. We mishear lyrics because of the powerful role expectations play in our hearing.

In the 1950s a Harper’s magazine writer coined the term “Mondegreens” for misheard lyrics, in reference to a Scottish folk song in which she heard the words “Lady Mondegreen” instead of “laid him on the green”.

This happens because the meaning we create from songs doesn’t come entirely from what we hear.

“There’s a piece of what we understand that comes from the sound that comes in our ear,” Mark Liberman, a linguist at the University of Pennsylvania, told PRI last November, but “there’s a piece of what we understand that comes from the expectations in our brain”.

6. You might be more likely to keep mishearing a lyric if you find the incorrect version amusing.

7. “Wannabe” by the Spice Girls is officially the UK’s catchiest song.

Scientists collected data from 12,000 people in an online game called Hooked on Music, created in collaboration between researchers and the Museum of Science and Industry (Mosi) in Manchester.

People were played clips, selected from more than 1,000 of best-selling songs since the ’40s, and had to indicate once they recognised the song. The average time it took to recognise a song was five seconds.

But the Spice Girls’ debut single “Wannabe” took people an average of just 2.29 seconds to recognise, according to the BBC.

8. Album sales in a particular genre of music go up as the music gets simpler.

9. People get chills listening to all different sorts of music.

Ever got goosebumps when listening to your favourite music? It turns out that it’s not the type of music that dictates whether you’ll get chills, but how much you’re into it.

A paper published in the journal Social Psychological & Personality Science found that musical preference didn’t make a difference when trying to predict whether someone is likely to get chills when listening to music.

In fact the study, which involved 196 mostly young adults from the University of North Carolina, found that “openness to experience” was the biggest predictor of who would get chills when listening to music. Openness to experience is a factor that predicts how much someone is into music, explains Williamson in a blog post about the paper. Essentially, this means that if you’re really into your music, whatever that music is, you’re likely to get the occasional shiver down your spine.

10. Music that gives you chills might make you more generous too.

Research published last year in the journal Frontiers In Psychology found that people were more likely to choose to give money to others if their favourite chill-inducing was playing. If music that they said they didn’t like was playing instead, they gave significantly less money. Just 22 people took part, so take the results with a pinch of salt, but it’s an intriguing finding.

Some are obvious: having heard the song recently and repeatedly can contribute. But so can seeing a single word that reminds you of that song (for example, Williamson says walking into a shoe shop called Faith led to George Michael’s song of the same name being stuck in her head all afternoon).

Even stress can trigger an earworm. One participant in an online survey Williamson organised got a song stuck in her head during a big exam when she was 16 – then at every stressful life event since then it reappeared, even years later.

12. The best way to get rid of an earworm might be to get a different song stuck in there.

Here’s some information that might help, though: Recent thoughts are likely to come back if you aren’t actually finished with the thought, according to a paper in Applied Cognitive Psychology. This fits with a different study published in PLOS One, in which some people report that playing your earworm all the way through, either in real life or in your head, can get rid of it.

If that doesn’t work, one way to game the system is to listen to specific music you don’t mind having stuck in your head. Then at least you can choose your earworm.

13. Cows produce more milk when listening to relaxing music.

And finally… as reported by the BBC in 2001, listening to relaxing music can lead to cows producing more milk. The study involved 1,000 cows being exposed to fast, slow, or no music for 12 hours a day over a nine-week period.

When listening to the slow music (e.g. “Everybody Hurts” by REM) the cows produced 3% more milk per day than when they listened to fast music (e.g. “Space Cowboy” by Jamiroquai).

“Calming music can improve milk yield, probably because it reduces stress,” Dr Adrian North, who carried out the study, told the BBC.

According to Modern Farmer, music is something the dairy industry had been playing about with before the psychologists got involved too. Dairy farmer Kristine Spadgenske from Minnesota told them: “At our farm you can always tell when the radio is not on because the cows are way more jumpy and less likely to come into the parlor.”